The present invention relates generally to apparatus and methods for separating constituents of blood and particularly relates to apparatus and methods for generating platelet concentrate from whole blood.
There are a number of automated, on-line donor hemapheresis systems for the separation of whole blood into two or more of its constituents. Such systems are designed to collect a predetermined volume of plasma from a donor using a fully automated processing program in conjunction with a hemapheresis instrument and a disposable tubing set or harness packaged separately from the instrument. In U.S. patent application Ser. No. 644,032, filed Aug. 24, 1984, now U.S. Pat. No. 4,776,964, there is disclosed a two-needle system for the continuous separation of platelet concentrate from whole blood. In that system, whole blood is first separated into platelet-rich plasma and packed cells, the latter being returned to the donor by way of the separate second needle. The platelet-rich plasma is then separated into platelet-poor or depleted plasma and platelet concentrate. While the two separations are performed sequentially, the system is continuous in that platelet concentrate is generated continuously while the system is connected with the donor.
Another automated system for separating blood into components, including platelet-rich plasma, is the CS-300.RTM. centrifugal separator sold by Baxter Healthcare Corp. of Deerfield, Ill., U.S.A.
There has also been developed an instrument which provides for alternate blood collection and packed cell reinfusion cycles through a single needle, while simultaneously and continuously separating whole blood into packed cells and platelet-rich plasma. Such platelet-rich plasma has a platelet count of approximately 600,000 platelets per microliter. To further concentrate the platelet-rich plasma, it has been the practice to send the container having the platelet-rich plasma to another location, i.e., a laboratory, where another separator is used to separate platelet concentrate from the platelet-poor plasma. The platelet concentrate, following a period of incubation, rest and then resuspension would then be stored until use. Such platelet concentrate has about 1.8 million platelets, or more, per microliter of plasma.
As will be appreciated, there is little world market for platelet-rich plasma directly inasmuch as clinicians do not transfuse platelet-rich plasma directly but do transfuse platelet concentrate.
Thus, platelet concentrate is the more significant product. However, the logistics of the secondary separation of platelet-rich plasma into platelet concentrate is significant inasmuch as generation of platelet-rich plasma from whole blood and concentrating those platelets into platelet concentrate is usually performed by different people, with different objectives. The latter requires a significant amount of attention and talent and there are many aspects of the procedure where error could affect the quality of the results. Thus, it is desirable to generate the platelet concentrate generally at about the time whole blood is taken from the donor and first separated into platelet-rich plasma, and have one person responsible for preparing the concentrate.
According to the present invention, the platelet-rich plasma is concentrated into platelet concentrate and platelet-poor plasma using the same instrument designed for producing platelet-rich plasma immediately following the taking of whole blood from the donor. Additionally, the procedure of the present invention for producing platelet concentrate does not subtract from or add to the critical donor connect time on the instrument as compared with the time on the instrument for producing platelet-rich plasma. That is, when producing platelet-rich plasma, there is usually a time period after the donor is disconnected from the instrument during which the donor rests in the donor chair next to the instrument and the instrument is not used. This time period is used to advantage in the present invention to further process the platelet-rich plasma to platelet concentrate by using the otherwise idle instrument. Consequently, the present invention concentrates platelet-rich plasma into platelet concentrate and platelet-poor or platelet-depleted plasma discontinuously with the initial collection and separation of whole blood into platelet-rich plasma and packed cells and after the donor has been disconnected from the collection and reinfusion harness set. Advantageously, platelet concentrate may be produced in accordance with this invention in conjunction with a novel tube set or harness which enables single-needle alternate collection of whole blood and reinfusion of packed cells while the separator continuously separates platelet-rich plasma from the whole blood.
To accomplish this, the harness set has first and second integrally connected tubing portions, each containing a separator. The first tubing portion contains a reservoir having dual compartments. After the first tubing portion is applied to the instrument and venepuncture is accomplished, collection of platelet-rich plasma is effected by alternately collecting anticoagulated whole blood and reinfusing packed cells. Simultaneously, the instrument and first tubing portion cooperate to continuously separate platelet-rich plasma and packed cells. Once a sufficient quantity of platelet-rich plasma is obtained, the first tubing portion is sealed, severed from the second tubing portion and disconnected from the instrument. The donor is also disconnected from the harness set. Thereafter, the second tubing portion is applied to the instrument for processing the platelet-rich plasma to generate platelet concentrate. It will be appreciated that the foregoing is accomplished in an entirely closed system thereby maintaining system sterility throughout. Moreover, the same operator who performed the venepuncture and obtained the initial separation of anticoagulated whole blood into platelet-rich plasma and packed cells also performs the platelet concentration. The latter may be effected during the time subsequent to blood collection when the donor is resting and the instrument is otherwise idle. Improved quality and control of this quality is thus achieved.
In accordance with a specific preferred embodiment of the present invention, there is provided a method for separating blood into constituents, comprising the steps of providing a first tubing portion having a first blood separator and a phlebotomy needle, applying the first tubing portion to an apheresis instrument, connecting the needle to a blood donor to supply whole blood to the first tubing portion, operating the instrument to flow whole blood to the separator, separating from the whole blood in the first separator a first-blood-constituent-rich plasma, providing a second tubing portion having a second blood separator, disconnecting the phlebotomy needle from the donor, removing the first tubing portion from the instrument, applying the second tubing portion to the instrument, operating the instrument to supply the first-blood-constituent-rich plasma to the second separator and separating the first-blood-constituent from the first-blood-constituent-rich plasma to provide a first-blood-constituent concentrate.
In accordance with another aspect of the present invention, there is also provided a method for separating blood into constituents, comprising the steps of providing a tubing set having first and second blood separators and a phlebotomy needle, applying part of the tubing set including the first separator to an apheresis instrument, connecting the needle to a blood donor, operating the instrument to flow blood from the donor to the first separator, separating from the whole blood in the first separator a first-blood-constituent-rich plasma, thereafter applying another part of the tubing set including the second blood separator to the instrument, operating the instrument to supply the first-blood-constituent-rich plasma to the second separator and separating in the second separator the first-blood-constituent from the first-blood-constituent-rich plasma to provide a first-blood-constituent concentrate.
In a further embodiment of the present invention, there is provided a harness set for application to an apheresis instrument, comprising first and second separators for separating blood into constituent parts, a phlebotomy needle, a first-blood-constituent-rich plasma collection container, first tubing means connected to the phlebotomy needle, the first separator and the container for supplying whole blood from a donor to the first separator for separation into a first-blood-constituent-rich plasma and for supplying the first-blood-constituent-rich plasma to the container, a first-blood-constituent concentrate collection container, second tubing means connected to the first-blood-constituent-rich plasma collection container, the second separator and the concentrate collection container for supplying the first-blood-constituent-rich plasma in the first-blood-constituent-rich plasma collection container to the second separator for separation into a first-blood-constituent concentrate and for supplying the concentrate to the concentrate container.
Accordingly, it is a primary object of the present invention to provide novel and improved apparatus and methods for generating platelet concentrate wherein a single microprocessor controlled hemapheresis instrument is used in conjunction with an integrated harness set having first and second tubing portions sequentially applied to the instrument to first produce platelet-rich plasma from the donor's anticoagulated whole blood and, thereafter generate platelet concentrate from the platelet-rich plasma after the donor has been disconnected from the harness set and instrument.
These and further objects and advantages of the present invention will become more apparent upon reference to the following specification, appended claims and drawings.